New Delhi: The newly developed bio-toilets being installed in Railways that treat human waste with bacteria will not only address sanitation problem but improve Rail safety, Union Minister Jairam Ramesh stressed on Wednesday.

After inspecting a train coach fitted with the bio-toilet at New Delhi Railway Station, the Minister for Drinking Water and Sanitation also said the work of retrofitting bio-toilets in coaches in trains has already started and by 2022 all 53,000 coaches will have eco-friendly toilets.

Noting that sanitation in Railways, which he once described as "world's biggest open toilet", is closely linked with rail safety, the Minister said "you must have clean railways for safe railways."

"The excreta being acidic... corrodes the track. Rail safety is jeopardised because of the free flow of excreta from the toilet on to the track.... Through this measure, if we are able to do it in 10 years time, it (the bacteria) will lick away the problem of sanitation in railways," the Minister told reporters here.

An MoU was signed in the month of July this year between Defence Research & Development Organisation and Ministry of Drinking Water and Sanitation under which bio-toilets developed by DRDO are being fitted in the existing as well as new rail coaches. In these biotoilets, humdan wate is treated by bacteria which is benign to humans and converts human waste into water and gases.

Ramesh also offered to share half the cost of retrofitting all existing 50,000 coaches with bio-toilets in the next ten years, which will come about Rs 250 crore each year.

Moreover, all new coaches (about 5,000 per year) will be fitted with eco-toilets in next two to three years time.

The Minister said the measure will not only prevent the corrosion of tracks but will also provide odourless toilets to passengers.

About 20 million passengers travel every day by train.

Senior Railway official Keshav Chandra said the DRDO developed biodigester is "the cheapest way of disposing human waste."

"Because the western toilets which are available in Europe and America...that would cost about Rs 30 lakh. That is three to four times costlier. This is also the cheapest form of disposing of human waste and the best," he said.